Newbie question on dataloging.

[wbjunkie]

Would like to data log various voltage and resistance values.
Also Engine RPM.

Have started with this
http://ww1.microchip.com/downloads/en/AppNotes/00990a.pdf
a. What would be a good PIC to use for this project
b. What kind of input voltage wise can the pic handle. On its analogue to digital input pins.

[skimask]

Guess it depends what sort of engine you're trying to do some datalogging on...

Single cylinder lawnmower engine - could probably get away with a 12F683
Datalogging on a B-36H, well, 168 cylinders, 336 spark plugs, 4x J47 jet engine, now you need something a bit more substantial...

Voltage inputs - It's all in your chosen PIC's 'Electrical Specifications' section of the datasheet.

[wbjunkie]

A regular 4 stroke 6 cylinder car engine.
Im trying to save some time here.
we both know a lawn mower engine will not have map, maf, tps, o2, coolant temp etc, servo motor position etc

[skimask]

we both know a lawn mower engine will not have map, maf, tps, o2, coolant temp etc, servo motor position etc
Other than the obvious economical reasons...Why not? As crazy as emission regulations are getting these day, I can see it happening sooner or later...either that or we all get electric mower and move the emissions concerns to the power plants! I attached a standard 3-wire O2 sensor to a 17HP Koehler exhaust awhile back, just to see what was what. Of course, by the time I leaned it out to stoich, it didn't have any leftover grunt to pull thru tall grass, and practically no acceleration.

You may be trying to save some time, so why not save us some time while you're at it...

Are we talking about an engine already installed in a vehicle? A production vehicle, such as a Chevy, or a Honda? Or a sort of homemade 'dune buggy' off-road type machine?
Fuel injected or carb'd?
Does it all matter? Well, yes, maybe no. Depends. A post '96 V-6 already installed in a production vehicle would be a relative piece of cake to get that data already formatted for you. Something a bit earlier, yes, that'll need a lot of analog signal conditioning before you can get reliable, repeatable results.

So....whatcha got?

[wbjunkie]

well obvioully its not a modern car for if it was then a 40$ ODB scan tool would tell me everything I need to know.
This more of a debug tool to use when your rushed for time. Track side or in the pit lane.
We typically have a mix of engines from a Chevy 1.6 to a suzuki 1.3 to a various other engines. All pre ODB. Or if they have ODB its not to an open standard. The company wants to sell you their 5000$ proprietary scan tool.

The idea is to just hook up each lead to each of the sensors. Signal conditioning has pretty much been covered in the Micro chip app note.
As you know typically all sensors will output a 0-5 volt voltage or a Resistive value. We basically need to know that the sensors are all working.
So your looking for RPM input at least 4 inputs for 0-5 volts and another 3 for resistance based measurements.

May have been faster for me to just read the data sheets.

[mackrackit]

And you did not tell us how much data you want to log and what you will do with it after you have logged it. Post process on a PC?

With all of the chips out there this is an open ended question, but one with plenty of ADCs and a fair amount of memory is the 18F6680. Or if you want almost unlimited log storage maybe a 16F877A and a VDIP1 or a SD card?

[skimask]

May have been faster for me to just read the data sheets.

Microchip website has a 'parametric search' tool. Select your parameters (i.e. number of A/D inputs, pin count, memory size, and so on) and it'll narrow down the chips based on those inputs.

[wbjunkie]

thanks guys
found this
http://www.dataq.com/products/startkit/di194rs.htm
24$ with software is cool.